<!DOCTYPE html>
<style>
  #contents {
    height: 500px;
    background-color: rgb(0,255,0);
  }
  #container {
    overflow-y: scroll;
    height: 224.352px;
    width: 50%;
    background-color: red;
    border: 1px solid gray;
  }
  #outercontainer {
    position: absolute;
    left: 0px;
    width: 575.06px;
    padding-left: 40px;
    padding-right: 0px;
    background-color: black;
  }
</style>
<div id="outercontainer">
  <div id="container">
    <div id="contents">
    </div>
  </div>
</div>
